Augustin Sayer (10 October 1790 - 15 November 1861) was a physician and sanitarian who was involved in the building of the sewerage and drainage infrastructure of London. Born in Bexley, Sayer's family moved to France, subsequently being held prisoner during the Napoleonic Wars. He became a licensed physician in 1820 and spent much of his career attempting to promote sanitary reform. He served as a member of the Metropolitan Commission of Sewers and of the sewers committee of the Marylebone vestry. He was the author of three books on the disposal of town sewage: